Scientific Genius

The scene is the launching pad of a large rocket which can be cut from a large piece of cardboard. There is an elaborate countdown, but the rocket fails to go off at zero. All those present inspect it and check on a number of highly-scientific-sounding devices - the supersonic sector wire; the exhaust fin fanstand; the sub-stabilizer exidizer, etc. All seem perfect. Finally the smallest boy says: "I've found the trouble. Somebody forgot to put in the fuel."